ZIP Code 21111 — Monkton, MD
21111 is a standard (street delivery) ZIP code serving Monkton, Maryland, in Baltimore County. To mail something here you only need these five digits — but the four-digit extension narrows delivery to a single point, and it is what USPS bulk postage discounts are priced on.
ZIP code 21111 at a glance
| ZIP code | 21111 |
|---|---|
| Primary city | Monkton |
| State | Maryland (MD) |
| County | Baltimore FIPS 24005 |
| ZIP type | Standard (street delivery) |
| Time zone | America/New_York |
| Population | 4,714 |
| Coordinates | 39.575680, -76.580890 |
How ZIP+4 works in 21111
The four digits after the hyphen encode a delivery segment inside 21111. In practice one segment usually means:
- One side of one block — odd numbers on a street between two cross streets
- A single large building, or one floor of it
- A group of PO boxes, sometimes a single box
- A single business that receives enough mail to warrant its own code
That is why 21111 has no single ZIP+4: two neighbors across the street from each other usually have different ones. Enter a street address above and we will return the exact nine-digit code along with the standardized USPS address format.
Nearby ZIP codes
Showing the closest twelve. See every ZIP code within 25 miles of 21111.
| ZIP | City | Distance |
|---|---|---|
| 21131 | Phoenix, MD | 5 mi |
| 21152 | Sparks Glencoe, MD | 5.6 mi |
| 21161 | White Hall, MD | 5.9 mi |
| 21013 | Baldwin, MD | 6.5 mi |
| 21084 | Jarrettsville, MD | 6.9 mi |
| 21120 | Parkton, MD | 7.1 mi |
| 21031 | Hunt Valley, MD | 7.3 mi |
| 21030 | Cockeysville, MD | 7.4 mi |
| 21047 | Fallston, MD | 8.3 mi |
| 21082 | Hydes, MD | 8.8 mi |
| 21023 | Butler, MD | 9.2 mi |
| 21057 | Glen Arm, MD | 9.5 mi |
Questions about 21111
What is the ZIP+4 code for 21111?
21111 is the five-digit ZIP code. The ZIP+4 adds four more digits that identify a specific delivery point — usually one side of a city block, a single building, or a group of PO boxes. Because those four digits change from address to address within 21111, you need to look up a specific street address to get them.
What city is 21111?
21111 is assigned to Monkton, Maryland, in Baltimore County.
Do I need to use the ZIP+4?
It is optional for ordinary mail, but it speeds up sorting and it is required for most USPS bulk-mail postage discounts. Many address-verification and e-commerce systems also use ZIP+4 to confirm a delivery point exists.
Need thousands of these?
Upload a CSV and get ZIP+4, county, carrier route, and delivery-point data appended to every row — or call the API directly.